hush: use ash's read builtin

function                                             old     new   delta
shell_builtin_read                                     -    1000   +1000
set_local_var_from_halves                              -      24     +24
setvar2                                                -       7      +7
...
popstring                                            140     134      -6
ash_main                                            1375    1368      -7
setvar                                               184     174     -10
arith_set_local_var                                   36       -     -36
builtin_read                                        1096     185    -911
------------------------------------------------------------------------------
(add/remove: 3/1 grow/shrink: 5/23 up/down: 1038/-1007)        Total: 31 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/hush_test/hush-read/read_ifs.right b/shell/hush_test/hush-read/read_ifs.right
new file mode 100644
index 0000000..b523344
--- /dev/null
+++ b/shell/hush_test/hush-read/read_ifs.right
@@ -0,0 +1,10 @@
+test 1: .a. .b. .c.
+test 2: .a. .b. .c.
+test 3: .a. .. .b,c.
+test 4: .a. .. .b,c.
+test 5: .a. .. .c.
+test 6: .a. .. .c. .d.
+test 7: .a. .. .b,c,d  ,  ,.
+test 8: .. .a. .b. .c.
+test 9: .a. .b. .c. ..
+test A: .. .a. .. .b. .c.